After 35 years in Congress, the late Rep. Edith Nourse Rogers said, “The first 30 years are the hardest.” Sen. Barbara Mikulski doesn’t see the challenges diminishing anytime soon.

On Saturday, the fiery, 4-foot-11-inch Democratic Senator from Maryland will surpass Rogers as the longest-serving female Member of Congress.

According to the Senate Historical Office, Mikulski will reach 12,858 days of service this weekend.

“I think the challenges have just changed,” Mikulski told Roll Call about her years on Capitol Hill. “But the challenges have changed because when we came, there was so few of us and we were considered a novelty.”

With 76 in the House and 17 in the Senate, women may no longer be a novelty in Congress, but they are still a minority — a fact of which Mikulski, who already received the title of longest-serving female Senator in 2011, is well-aware.

During an interview, Mikulski seemed more interested in talking about contraception, the retirement of longtime friend and moderate Republican Sen. Olympia Snowe (Maine) and diminished bipartisanship than about her personal accomplishments.

“Now, where we are, though our numbers have increased,” she said, “we see in the public policy arena that there is more partisan prickliness.”

Considered by many of her colleagues as a friend and mentor, she is guided by a Catholic belief in social justice, her role as dean of Senate women and a faith in bipartisanship — not reflected in her liberal voting record — all endowed by her quick-witted sense of humor.

A Nod to the Nuns

Mikulski can tally a number of “firsts” from her time in Congress, among them: first woman elevated to a leadership post in the Senate, first female Democrat to serve in both chambers, only current Member of Congress in the National Women’s Hall of Fame and one of the first women to wear pants on the Senate floor.

She attended Catholic school and to this day extends thanks for her accomplishments to the nuns who steeped their charges in the doctrine of social justice.

“I feel that I am my brother’s keeper and my sister’s keeper,” she said. “I think that’s why I am shaped by the words of Jesus himself: Love thy neighbor. And I took it seriously.”

Born in 1936, Mikulski, a third-generation Polish American, grew up in working-class East Baltimore, an area where she established not only her political roots but her adherence to assisting the less fortunate.

Her parents ran a grocery store called Willy’s Market, and it opened early every morning so that steelworkers could buy lunch before their morning shifts.

“In his grocery store, when people would be having a hard time, he would always extend credit, a helping hand,” she said. “If someone was laid off or unemployed ... their family wouldn’t go hungry as long as Willy Mikulski was their grocer,” she said. “I learned that we are all in it together. It’s not always that we’re blood family, but it’s your extended family that we really have to be considerate of.”

A social worker by trade, she entered politics as a neighborhood activist: She won a city council seat in 1971 after a successful battle against a highway project.

After losing her first bid for Senate in 1974, she won a seat to the House in 1976. She served five terms before moving to the Senate in 1987.

Her chief legislative accomplishments reflect her attitude about government being an engine of social justice: allowing Medicaid recipients to protect certain assets while getting assistance in paying for a spouse’s nursing-home care and a 2009 law clarifying time limits for workers to file employment discrimination lawsuits, known as the Lilly Ledbetter Fair Pay Restoration Act.

Mikulski calls the 2010 health care overhaul law one of the “greatest social justice initiatives” in which she has participated.

“She is very loyal and fierce friend,” said Benjamin Cardin, Maryland’s junior Democratic Senator, on one of his morning drives to Washington. Cardin said he remembers Mikulski from her city council work. “She’s a remarkable person. I tell ya, she really does represent the best of Maryland.”

Less Shove, More Push

A portrait of Rogers, a Massachusetts Republican who died in 1960, hangs in the Cannon House Office Building hearing room for the Veterans’ Affairs Committee. After winning her seat, she said: “I hope that everyone will forget that I am a woman as soon as possible.”

That’s not a sentiment Mikulski, co-author of a book about women in the Senate, would be likely to echo.

Outside the Appropriations Committee, Mikulski is not known as a champion of bipartisanship — her lifetime party unity score in the Senate is about 94 —or a practitioner of civil discourse — during the recent debate on the administration’s birth control mandate she accused Republicans of waging “a systematic war against women.’’

But, even as she has rarely been one to tone down her own partisan rhetoric, she makes a plea for more civility on Capitol Hill.

Mikulski said bipartisanship has diminished on Capitol Hill since she arrived, a conclusion highlighted by the recent retirement announcement of Snowe.

“I would hope as I commemorate this, we go back to what I found when I first came to the Congress, which is a spirit of bipartisanship,” she said. “I saw that in the way Tip O’Neill and Bob Dole and Howard Baker all could work together, both sides of the aisle, both sides of the Dome. When push came to shove, there was less of a shove, and more of a push, to get the job done.”